Boeing 787 Passes Incredible Wing Flex Test

Boeing has completed one of the more spectacular tests of the 787 Dreamliner program. The airplane maker completed the “ultimate-load wing-up bending test” on Sunday using airframe ZY997, the test aircraft that is basically built to be tortured on the ground and never fly.

During the test, the wings on the 787 were flexed upward “approximately 25 feet” which equates to 150 percent of the most extreme forces the airplane is ever expected to encounter during normal operation. The test is used to demonstrate a safety margin for the design and is part of the certification process to show the airplane can withstand extreme forces.

Ultimate wing load testing is standard procedure for any new airplane design and has been done on aircraft large and small almost since the beginning of aviation. Often simple sandbags are placed on the wing of an aircraft to represent the maximum forces needed to be tested. Boeing and other large plane makers use elaborate testing structures (pictured above) that flex the wings to apply the necessary forces. In the past, Boeing has flexed the wing beyond the required 150 percent, and more than once the company has flexed the wings of a new design to the failure point. The most recent example was in 1995 with the 777.

It had long been wondered if Boeing would flex the composite wings of the 787 to failure, but the company said they only went to 150 percent, and no further. An issue with the wing where it joins with the fuselage led to a major setback for the 787 program last year. The problem was fixed and a Boeing statement regarding Sunday’s test said the initial results from the test are positive and more analysis is being done.

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